It took years, but he finally double booked himself. A book tour that he'd been putting off caught up to him, and he had no choice but to go. It didn't help things that he wrote it down wrong, showing her on the calendar where he had written down April 27th as his tour date. So when Paula called on 22nd and asked him if he was ready to go in five days, it surprised them all. Alexis and her husband had made arrangements for him and Kate to take the kids while they took a well-deserved vacation in Europe, thinking that Castle would be happy to spend time with the grandkids on his birthday.

Alexis called them before they had time to break the news to her, insisting on speaking to Kate. "You don't have to do it if you don't want to." Her step-daughter had insisted. Kate could hear the panic in her voice, her boys chattering away in the background.

"It's okay! I'm planning on calling Martha later about watching Char during the day while your Dad is away, I'm sure she wouldn't mind keeping Jake company too. And I can pick up Owen from school when I get Oliver and Beth."

The younger woman sighed on the other end of the line. "Are you sure? That's five kids you have to be in charge of by yourself."

"Alexis, I can handle it. I promise."

The other end was silent as the girl thought, and Kate could picture her standing by her counter, her hand on her head as she worked everything out. "Okay." She conceded, her voice still hesitant. "But if you need anything, just call, and I will be on the next plane home."

Kate laughed, trying to calm her step-daughter's anxiety. "Don't worry, the boys are always a delight, just like you. I'll be fine. Castle took the phone from her then, reassuring his daughter while Kate ran upstairs to tell Oliver to clean his room while she pulled out the trundle bed.

Castle left the same day the boys arrived, early in the morning before the kids woke up. He woke his wife with a cup of coffee, his bag slung over his shoulder and a lingering kiss on her lips. "Are you sure you'll be okay?"

She let out a breath as she sat up, reaching for the coffee he'd placed on her nightstand. "What is it with the Castle's thinking I can't handle this?"

"It's not that I think you're incapable, it's just a lot of work that you thought you'd have help with." His voice was laced with concern as he sat on the bed next to her, his hand on her knee. "I've screwed up a lot of things before, but I never thought I'd have a tour I wasn't planning on."

"Well, it was bound to happen eventually." She chuckled, sipping the warm liquid and clearing her head. "Besides, your Mom is happy to watch the little ones during the day, and if I need extra hands, my Dad is retired now and he lives for the kids. Plus, Ryan and Espo can help me scare them straight if it comes to it." Her hand found his face, her thumb tracing his cheekbone as she convinced him. "I have plenty of help. We'll be fine." He nodded, his shoulders relaxing as she calmed him, a soft smile pulling at the corners of his mouth. She leaned up to kiss him, and he met her halfway, allowing her to wrap her arms around his neck and pull him in closer. She hated long book tours, she always had. It got easier once she had children to distract her, but she missed her husband when he was gone. After a moment, she pushed him away, laughing. "I hate to ruin the moment, but you're gonna be late."

"That's not how I want to start this tour." He leaned in for one last peck before rising from the bed, his bag adjusted on his shoulder. As if on cue, his phone began to ring, the death march ringtone making Kate smirk as she stretched in bed. She heard him answer as he left. "Yes Paula, I'm heading out the front door now." Kate stayed in the bed for a bit after he closed the door, her coffee cup gripped in one hand as she fought to wake up. And when she'd finished her drink, she stepped out of bed, the floor cold beneath her feet, and prepared for the extra visitors.

When Alexis dropped the boys off, Kate had already prepared a feast. Jake clung to his mother, his hand holding tightly to her pant leg, a giant giraffe wrapped in his other arm. Owen ran into the living room, waving at Kate as he passed, and sitting on the couch next to Oliver, showing his something on his DS. Kate stepped away from the oven for a moment, bending down to offer her youngest grandson a piece of bacon. Jake smiled, taking it from her and throwing his arms around her neck. "Hi, Nona."

"Hey, you!" She pressed a kiss to the timid boy's cheek. "You and Char are going to have so much fun together."

"And you can call me and Daddy every night." The redhead's hand fell to his hair as she spoke, her voice soothing and her touch relaxing him.

The boy pulled back, his dark eyes meeting his grandmother's, his face serious. "Nona, you and Grandpa got rid of all the monsters, right?"

She grinned. "Are you kidding? Of course we did! We haven't had a monster sighting in ten years!" She dropped her voice, pulling his ear to her mouth. "They're afraid of police officers, so they don't come around here."

"Good!" He sighed out his relief, his smile growing across his freckled face.

Kate pointed toward the living room. "Char and Beth are in there watching Ms. Frizzle. I think they'd like it if you joined them." Jake grinned and took off, shouting out to his family as he went.

Alexis wrapped Kate in a hug, pouring out her gratitude before launching into instructions. "Owen's school uniforms are in this bag, along with an extra jacket just in case he spills something on it. Fridays are casual, so he has an outfit to wear on that day if he wants to. I try not to let him watch television after school, but he can as long as his homework is done, because this whole stay is a treat for him." She pulled a smaller bag out of her purse. "Jacob's epi-pen is here, not that I expect there to be any bees yet, but just in case. If you catch it early enough, Benadryl is enough to stop a reaction, just watch him really close."

"Of course." Kate took the bag and left it on the counter, reminding herself to talk to Martha about it when she came to watch the little kids. When she turned back around to face the younger woman, she found Alexis watching her boys, her hands clutched around her waist, a worried look on her face. "What's the longest time you've left them for?"

A chuckle escaped Alexis' throat, her body relaxing. "It's that obvious, huh?" Her smile was soft as she reassured herself. "Just for the weekend, when you and Dad take them. Never a week."

"Well, they'll be fine, I promise."

"I know." She looked at the clock and started making her way to the living room. "I'm gonna be late." Her boys met her halfway, throwing their arms around her and allowing her to press kisses to their heads. She ruffled Jacob's dark hair, adjusted the collar on Owen's uniform, and headed back toward the kitchen. She hugged Kate one last time, whispering "thank you" one last time before scurrying out the door.

Kate moved back to the stove, taking the last of the bacon out of the pan, and spreading butter on the last pieces of toast. "Alright, who is hungry?" She called toward the living room, chuckling to herself as five little heads all turned in her direction.

The week went by without too much trouble. Martha was more than delighted to spend her days with her youngest granddaughter and great-grandson, typically bursting into the loft before breakfast was ready, exciting all five of the youngsters. Espo was more than capable of running a precinct, following her instructions to the letter each time she left and keeping her well informed about their case. Her Dad had even surprised her for dinner one night, stopping by with a hot meal in the crock-pot, taking some of the pressure off of her. Oliver quizzed Elizabeth and Owen on their spelling words every night while Kate chased and bathed the two youngest children, and she would go over his with him in the mornings at breakfast. She never had to worry about Owen watching too much TV, because as soon as he finished his homework, he was upstairs playing make believe games with his uncle and aunts. And by Friday, Kate wondered why everyone thought she'd have so much trouble. Sure, it was exhausting, but everything seemed to be running like a well-oiled machine.

On Friday night, Kate set up cushions and mattresses in the living room, gathered every thick blanket she could find in the house, and pulled a selection of Disney movies off the shelves. Three large bowls of popcorn were placed in strategic locations, and strings of white Christmas lights were hung along the ceiling to look like stars.

"It's like a camp-out!" The youngest of the group, Charlotte, jumped around as she squealed, dancing in circles on the couch cushions.

"Exactly!" Kate enthused back, pulling one of the popcorn bowls out of range of the young girl's spinning arms, even though she knew she would be vacuuming up a huge mess tomorrow. Her eyes scanned the other children in the room, settling on Jacob, who looked the most concerned. "It's because you all were so well behaved this week, and I thought you deserved a treat."

"Are we gonna sleep out here?" Jacob's small voice asked, his stuffed giraffe, Myka, clutched in his arms.

"If you'd like to. I already checked for monsters." As if she was reading his thoughts, the young boy relaxed, his shoulders dropping as he joined Charlotte in her dance. Kate waved her arms toward the stairs. "So let's go! Get on comfy jammie and let's get this marathon started!" With that, five pairs of feet galloped up the stairs, each of the kids shouting about which pair of pajamas they wanted to wear. Kate made her way into her own bedroom, pulling out the pair of fuzzy Tardis pajama pants that Castle had bought her for Christmas and a grey NYPD t-shirt. She waited on the couch as all five children came back downstairs one by one. And then they started the marathon.

It started with Wreck it Ralph, a family favorite amongst the kids. After Tangled, the pizza arrived, and they took a break to eat at the table. During Toy Story, Kate's phone rang, the 12th popping up as the caller ID, so she took the call into her bedroom, leaving the kids alone.

Ryan had caught a lead in their case that opened up about fifty new suspects. Plus, they had a lead that may have led to a narrower suspect pool, but needed supervisor approval for wires and cameras. And he needed them quick, which meant she had to perform some bureaucratic magic. After some time she managed to cut through the red tape and get him what he needed, and was able to rejoin her family.

In the living room, the kids were whispering, and Elizabeth let out a loud, "shhh," when she saw her mother approaching.

"What's going on out here?" Kate asked them, sinking down into the couch again.

"Nothing." Owen answered, unable to hide his mischievous smile. "We're just watching a movie."

She laughed, looking at all of the children, noting how none of them would meet her eye. "Sure you were. Nothing fishy here."

"Nope." Oliver and Elizabeth answered in sync.

She could have pursued it. She could have pushed them until they broke. But at the same time, she didn't want to ruin their fun. It couldn't be all that bad.

Peter Pan went in next, then Frozen, but by the time that was halfway over, all five of the kids were snoring, wrapped up in comforters, popcorn in their hair. Staying on the couch wasn't an option anymore, so she instead left her bedroom door open, just in case they needed her, and fell quickly into a deep sleep.

She awoke the next morning to the smell of fresh brewed coffee, and the sound of chattering children in the other room. Stretching her arms out, she connected with a small body on Castle's side of the bed. It was charlotte, her brown hair ruffled and her blue-green eyes squinting in the morning light. "Hey, snuggle bug. What are you doing here?"

The girl shrugged. "I had a bad dream, so I came in your bed."

Kate rolled over, showering her youngest with kisses, listening to her giggle and squirm. "I'm sorry, sweetheart. Did you sleep well once you got in bed with me?"

"Yeah."

Kate brushed hair out of her daughter's face. "Are you hungry? Do you want some breakfast?"

"Yeah." She answered again, this time wrapping her arms around her mother's neck, letting Kate lift her out of bed.

Kate grunted as she did it, her arms wrapping around her daughter's small frame as they made their way into the kitchen. "You're almost getting to be too big for this."

In response, the young girl buried her head in her Mother's neck, her hair tickling Kate's nose. Kate set her down by the island, the mug of coffee staring her in the face. "Thank you Ol for making coffee!" She called out to the living room, pulling the steaming mug towards her.

"No problem, Mom. Dad wasn't here and you were still asleep, but I tried my best." Her oldest answered, leaning against the island.

"That was very sweet of you. We have to call him in a couple of hours, wish him a happy birthday before he starts his day." The mug was poised at her lips, waiting for her to finish her sentence before pouring the sweet liquid down her throat.

"Of course!" Oliver answered. But she couldn't say anything else. The drink she had poured down her throat was not sweet, and instead tasted like she had swallowed an entire salt lick.

As she spit out the coffee and yelped in horror, a chorus of voices rang out, "April fools!" Elizabeth and Owen high fived each other while Oliver giggled and Kate dropped the cup in the sink.

"I don't know why I didn't expect that." She laughed, pulling another cup down from the cupboard.

It surprised her when Elizabeth pulled it out of her hand, walking it over to the coffee pot, where Oliver was waiting. "We'll make you a new one now." She promised, her blue eyes dancing with laughter. "No jokes this time, I swear."

"There better not be." She teased, opening the fridge and handing the skim milk to her son. After a quick glance at the contents of the fridge, she turned back to the group. "Looks like I'm out of eggs, so it's cereal for breakfast. Tell me what you want."

Five voices all piped up at once, but somehow she managed to pull down the three boxes she needed. Elizabeth brought her bowls, and Kate started pouring the Lucky Charms for Jacob. Except instead of marshmallows and frosted pieces, small brown squares with sugar embedded in it came out. Someone had switched the bags. The giggling intensified as she poured, Owen whispering, "April fools," as she handed the bowl of Life to Elizabeth. Kate expected the Life cereal box to be filled with Lucky Charms, but she again was met with surprise as brightly colored loops fell out instead. She poured three bowls of this for Oliver, Owen, and Charlotte, and sent them on their way. In the Fruit Loops box is where she finally found the Lucky Charms, the young Jacob impatiently shuffling his feet next to her as he waited for his bowl.

As the kids sat down to eat, Kate started to make her way through the kitchen. "What other surprises do you have hidden around here?" At the chorus of giggles from the table, she knew she was far from finished with the April fools pranks, and spent some time fixing cereal bags, switching labels on spices, and moving the pots and pans back to their original cabinet. As they clanged together, she wondered just how exhausted she was if they moved all of this while she slept. When the Tupperware was moved out of the cabinet for the pots and pans, and back into their proper cabinet, she poured herself a bowl of cereal and sat at the table.

A quick headcount told her she was down one kid. Her son, the oldest and sanest of the group, had disappeared, his cereal bowl untouched. And when she craned her head to peer into the living room, he wasn't there either. "Oliver?" She yelled, making the younger kids jump.

In a few seconds, he came shuffling out of her bedroom, Jacob's giraffe held above his head in triumph. "I found Myka!"

Kate's eyebrows knotted together. "Myka was missing?"

Oliver dropped the giraffe into Castle's empty seat, resuming his place at the table. "Yeah. We were looking this morning." His hazel eyes flicked over to Jake, whose brown eyes were shining. "You must have left her in the bathroom this morning."

Kate's hands came down, causing glasses to clatter and children to jump. "What did you do to my bathroom?"

Elizabeth broke first, her nervous laughter making the other kids giggle. "Nothing, Mommy." Her wide blue eyes looked innocent enough, and Kate felt her shoulders relax. "It was too close, we were afraid of waking you up."

Kate felt her eyes rolling despite the smile stretching across her face. "Gee, thanks." As the children finished eating, they dropped their bowls in the sinks and returned to the living room, wrapping themselves in blankets as the watched stuff on Netflix. Oliver and Kate were the last to finish, the young boy seemingly oblivious to Kate's studying of him. Not that watching him so intently would reveal any other pranks, but in ten years of existence, she had picked up on things that showed he was hiding something. Like how he wouldn't meet her eye, either looking toward the living room where he could just see the television, or staring down at his cereal bowl like he thought something would pop out of it. He ate slower too, his bites more deliberate, less on his spoon than what was typical for a growing boy, like he wanted to wait around and watch what happened next.

Kate shrugged off the feeling, content to let whatever happened, happen. This wasn't something they'd ever been able to do. Other than pranking Castle one year into thinking that they forgot all about his birthday, the birthday festivities usually outshone any of the minor pranks.

When they finished, Kate took his bowl from him and made her way to the sink. Sponge in hand, she turned on the water just to be sprayed in the chest by the hose. As the turned the water back off, she bit her smirk back, listening to Oliver roar with laughter at the table. His "April fools" went unsaid, as he instead wiped tears from his eyes. Kate inspected the prayer, finding a single, clear elastic holding down the button so she wouldn't see it. "You know, I did that same thing when I was younger to my Mom, and she made me clean up all the water."

"I promise, I'll clean it all up." He assured her with a smile, his eyes lit up as he watched her further.

She snapped the rubber band off the sprayer, turning on the faucet again just to be sprayed with even more water. This time it was more erratic, and soaked her from head to toe. Now as she turned it off, she heard laughter from all five children, who had gathered around the island to watch the chaos unfold. Kate wiped her eyes and pulled a small piece of tape off of the faucet, shaking her head as she held it up for all to see. "Fool me once. I should have checked, that one is on me."

Elizabeth and Owen had tears streaming down their faces as they moved toward the sink, their hands moving her away. It was Owen who spoke first, finding the breath and calming himself. "Go change, Nona. We'll clean up." Kate did as they said, shaking her wet arms about and flinging water back on all of them before retreating to her bedroom.

There she picked up her phone, tapping out a quick message to her husband. Boy do I have a story for you. I'm sure the kids will tell you all about it when they call you later. Come home soon! She tossed the phone on the bed and made her way to the dresser, grabbing the first t-shirt that her hands came in contact with. Except she didn't get just one. She realized with a laugh what her oldest had really been doing in here. Each shirt was pinned to the one underneath it, like an accordion. "Well played." She unpinned the first shirt, and grabbed a pair of yoga pants from the drawer below, placing them on the bed. Her clothing was clinging to her, and the air had cooled, so she was shivering as she changed. She went to slip her feet into her slippers once she was all dry, her eyebrows knitting together as she realized they didn't fit, and picked them up to inspect them.

That's when the door opened, Charlotte grinning from ear to ear as Kate held out three cotton balls that were stuffed inside. "April fools, Mommy!"

Kate's smile was warm as she lifted her youngest girl. "Did you do this?"

Charlotte nodded, blue-green eyes dancing with excitement, a smirk on her face. "Me and Jake did this morning!"

"That is probably the best prank yet! You'll have to tell Daddy when we call him later."

"Uh-huh!" She wiggled until Kate put her down, running into the other room, where the older kids were sitting.

Kate ruffled Oliver's hair as she moved to sit next to him, pulling him in and kissing his temple. "That was a good one, with the shirts."

When he turned to look at her, his own smile wide, all Kate could see was his father reflecting back at her. "I know, right? I thought you'd get a kick out of it."

Her hand trailed up and down his back, her smile warm as she relaxed. "Okay, just so I don't have a heart attack or anything, how many more pranks like that can I expect?"

"None." Owen answered, his head shaking back and forth, eyes glued to the screen. "You found them all."

"Good." Kate sat back in the couch, letting Jacob crawl up in her lap, his giraffe forgotten at the table. She stroked his dark hair, letting him relax into her. With a smile, she rested her head on his shoulder, speaking more to him than to anyone, but knowing the response it would cause from everyone else. "Did I ever tell you the story about how your mom, Grams and I tricked Grandpa?"

Oliver spoke first, reaching for the remote and pausing the TV. "I love this story!"

"Tell it again, Mommy!" Elizabeth shouted from inside her blanket cocoon.

"What did Mom help you do?" Owen piped up from his perch in the chair next to them.

Charlotte didn't speak, just climbed on the couch and wrapped her arm around Kate, listening with a tilted head and wide eyes.

"Well," Kate began, holding her grandson tighter in her lap, "It all started when your Mom gave Grandpa a pair of binoculars."